Many authors claim that students' attention declines approximately 10 to 15 min into lectures. To evaluate this claim, we reviewed several types of studies including studies of student note taking, observations of students during lectures, and self-reports of student attention, as well as studies using physiological measures of attention. We found that the research on which this estimate is based provides little support for the belief that students' attention declines after 10 to 15 min. Most studies failed to account for individual differences in attention. Our findings indicate that instructors should take into account individual differences in student attention when lecturing and determine whether students are recording the relevant content of the lecture in their notes.